CCM Gateway Trunks Test

Phone calls can be routed over the IP network using a trunk interface configuration in CUCM. The definition of trunk is expanded beyond physical connections such as a PRI, T1, or analog trunk, to also include virtual connections between two entities. The virtual connection defines a TCP/IP session between the two entities that is used for call signaling, and associated with the connection is a path over a TCP/IP network used for the media. The signaling path and the media path may terminate on different sets of endpoints and also may take different paths through the TCP/IP network. In some cases the trunk may define an entity that is the destination where the VoIP media stream of the call ultimately terminates, or it may define an entity that provides an intermediate routing function. In the first case, there must exist a separate configuration for each pair of endpoints, and the relationship between the two entities is peer-to-peer. In the latter case, a single trunk may be defined to specify a gatekeeper that provides a routing function between all entities registered to that gatekeeper. This relationship is one-to-many. In Cisco Unified Call Manager, trunks may be configured with one of two protocols: H.323 or SIP.

When Cisco Unified Communications Manager receives a call setup request from a local endpoint or from another call control system, then the manager analyzes the target of the received request to find the best matching entry in its call-routing table. The source of the call setup request can be through trunk, gateway or IP phone. A call request received through a trunk is looked up in the call-routing table. Then the manager forwards the call setup request to the destination device that is associated with the matched call-routing table entry. But, when the trunk is inactive or busy, then the call setup request cannot be established leading to termination of the call request. This can cause serious service level bottlenecks.

This test monitors the gateway trunks in the Call Manager and reports the number of trunks that are active. This test also reveals the number of gateway trunks that are inactive, busy and unknown. This helps administrators to proactively detect any unavailable trunks and resolve the issue before the end user is affected.

Target of the test : A Cisco Unified Communications Manager

Agent deploying the test : An external agent

Outputs of the test : One set of results for the target Cisco Unified Communications manager being monitored

Configurable parameters for the test
Parameters Description

Test period

How often should the test be executed


The IP address of the host for which this test is to be configured.


The port at which the monitored target exposes its SNMP MIB; the default is 161.


By default, the eG agent supports SNMP version 1. Accordingly, the default selection in the SNMPversion list is v1. However, if a different SNMP framework is in use in your environment, say SNMP v2 or v3, then select the corresponding option from this list.


The SNMP community name that the test uses to communicate with the firewall. This parameter is specific to SNMP v1 and v2 only. Therefore, if the SNMPVersion chosen is v3, then this parameter will not appear.


This parameter appears only when v3 is selected as the SNMPversion. SNMP version 3 (SNMPv3) is an extensible SNMP Framework which supplements the SNMPv2 Framework, by additionally supporting message security, access control, and remote SNMP configuration capabilities. To extract performance statistics from the MIB using the highly secure SNMP v3 protocol, the eG agent has to be configured with the required access privileges – in other words, the eG agent should connect to the MIB using the credentials of a user with access permissions to be MIB. Therefore, specify the name of such a user against this parameter. 


This parameter appears only when v3 is selected as the SNMPVERSION. An SNMP context is a collection of management information accessible by an SNMP entity. An item of management information may exist in more than one context and an SNMP entity potentially has access to many contexts. A context is identified by the SNMPEngineID value of the entity hosting the management information (also called a contextEngineID) and a context name that identifies the specific context (also called a contextName). If the Username provided is associated with a context name, then the eG agent will be able to poll the MIB and collect metrics only if it is configured with the context name as well. In such cases therefore, specify the context name of the Username in the Context text box.  By default, this parameter is set to none.


Specify the password that corresponds to the above-mentioned Username. This parameter once again appears only if the SNMPversion selected is v3.

Confirm Password

Confirm the AuthPass by retyping it here.


This parameter too appears only if v3 is selected as the SNMPversion. From the Authtype list box, choose the authentication algorithm using which SNMP v3 converts the specified username and password into a 32-bit format to ensure security of SNMP transactions. You can choose between the following options:

  • MD5 – Message Digest Algorithm
  • SHA – Secure Hash Algorithm


This flag appears only when v3 is selected as the SNMPversion. By default, the eG agent does not encrypt SNMP requests. Accordingly, the this flag is set to No by default. To ensure that SNMP requests sent by the eG agent are encrypted, select the Yes option. 


If this EncryptFlag is set to Yes, then you will have to mention the encryption type by selecting an option from the EncryptType list. SNMP v3 supports the following encryption types:

  • DES – Data Encryption Standard
  • AES – Advanced Encryption Standard


Specify the encryption password here.

Confirm Password

Confirm the encryption password by retyping it here.


Specify the duration (in seconds) within which the SNMP query executed by this test should time out in this text box. The default is 10 seconds.

Data Over TCP

By default, in an IT environment, all data transmission occurs over UDP. Some environments however, may be specifically configured to offload a fraction of the data traffic – for instance, certain types of data traffic or traffic pertaining to specific components – to other protocols like TCP, so as to prevent UDP overloads. In such environments, you can instruct the eG agent to conduct the SNMP data traffic related to the monitored target over TCP (and not UDP). For this, set this flag to Yes. By default, this flag is set to No.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Unknown trunks

Indicates the number of trunks in an unknown state for the Communications Manager.



Active trunks

Indicates the number of trunks in an active state for the Communications Manager.



Busy trunks

Indicates the number of trunks in busy state for the Communications Manager.



Inactive trunks

Indicates the number of trunks in an inactive state for the Communications Manager.


A low value is desired for this measure.